Method and device for feeding reels to a machine

ABSTRACT

A device ( 2 ) for feeding reels ( 3 ) has a manipulator ( 14 ) having a gripping member ( 19 ) for picking up one reel ( 3 ) at a time off a pallet ( 16 ) and transferring the reel ( 3 ) to an unwinding pin ( 4   a   ; 4   b ) on a machine ( 1 ); the gripping member ( 19 ) is enabled to pick up a reel ( 3 ) off the pallet ( 16 ) when at least one reference point (k 1 ) of the gripping member ( 19 ) lies inside a central hole ( 7 ) of the reel ( 3 ).

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/IT02/00313 which has an Internationalfiling date of May 13, 2002, which designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to a method of feeding reels to a machine.

More specifically, the present invention relates to a method of feedingreels to a machine defined by a cigarette packaging machine, to whichthe following description refers purely by way of example.

BACKGROUND ART

Cigarette packaging machines now operate at such high output rates as torequire large amounts of packaging material, which is partly supplied inthe form of strips wound into reels. Each reel comprises a strip ofpackaging material wound about a spool having a central hole, and isfitted onto an unwinding pin on the packaging machine. The strip ofpackaging material is unwound off the reel, and sheets of packagingmaterial are cut off the strip and folded about groups of cigarettes.

The increase in the amount of packaging material required calls forautomatic reel handling to speed up reel feed to the machine, which inturn calls for determining the position of the reel to enable a reelmanipulator to grip the reel by means of a gripping member and align thereel with an unwinding pin on the packaging machine.

Patent EP-A-551,854 relates to a manipulator featuring a reel grippingmember and for picking reels off a pallet on which the reels arearranged with their respective axes positioned vertically. The grippingmember has a TV camera for picking up an image of a reel; and anarithmetic unit for processing the image data by means of an algorithmbased on translation and inversion of the image to determine thecoordinates of a characteristic point on the reel. Once the coordinatesof the characteristic point on the reel are determined, the manipulatorsets the gripping member to a given position to grip the reel correctly.

Though reliable and capable of transferring a large number of reels perunit of time, the arithmetic unit of the above manipulator forprocessing the points in the image is relatively expensive.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a straightforward,low-cost method of feeding reels to a machine.

According to the present invention, there is provided a method offeeding reels to a machine from a store of reels close to said machine;each reel having an axis, a central hole which is engaged by anunwinding pin on said machine, and two flat faces perpendicular to saidaxis; and the method being characterized by determining whether at leastone reference point of a gripping member of a manipulator lies insidethe hole of a reel in the store; picking up said reel by means of thegripping member when the reference point lies inside the hole of saidreel; and transferring said reel from said gripping member to saidunwinding pin.

The present invention also relates to a device for feeding reels to amachine.

According to the present invention, there is provided a device forfeeding reels to a machine from a store of reels close to said machine;each reel having an axis, a central hole which is engaged by anunwinding pin on said machine, and two flat faces perpendicular to theaxis; and the device being characterized by comprising a manipulatorhaving a gripping member for picking up a reel from said store when atleast one reference point of the gripping member lies inside the hole ofsaid reel.

BRIEF DESCRIPTION OF THE DRAWINGS

A number of non-limiting embodiments of the present invention will bedescribed by way of example with reference to the accompanying drawings,in which:

FIG. 1 shows a view in perspective, with parts removed for clarity, of apackaging machine featuring a reel feed device in accordance with thepresent invention;

FIG. 2 shows a larger-scale underside view of a gripping member of theFIG. 1 device;

FIGS. 3 and 4 show schematic side views of a variation of the grippingmember in two operating positions with respect to a reel;

FIGS. 5, 6 and 7 are schematic plan views showing the position of agripping member of the FIG. 1 device with respect to a reel.

BEST MODE FOR CARRYING OUT THE INVENTION

Number 1 in FIG. 1 indicates as a whole a cigarette packaging machinefor producing packets of cigarettes not shown.

Machine 1 comprises a feed device 2 for supplying reels 3; and twounwinding pins 4 a and 4 b for unwinding reels 3. Pin 4 a is shown in aposition supporting a reel 3 being unwound; and pin 4 b in a position toreceive a reel 3 from feed device 2.

Each reel 3 has an axis 5, and comprises a spool 6 having a hole 7; anda strip 8 of packaging material wound about spool 6 to form twoparallel, substantially flat lateral faces 9 perpendicular to axis 5,and a substantially cylindrical face 10 parallel to axis 5.

Machine 1 comprises a frame 11 supporting unwinding pins 4 a and 4 b,each of which has an axis 12 and a drive member 13 for switching pin 4a, 4 b between the unwinding position in which axis 12 is horizontal,and the receiving position in which axis 12 is vertical.

Device 2 for feeding reels 3 comprises a manipulator 14 for manipulatingreels 3, and a platform 15 for supporting a pallet 16 on which reels 3are arranged in orderly manner with respective axes 5 positionedvertically. Manipulator 14 comprises an articulated arm 17 fixed at oneend to frame 11 to rotate about a vertical axis 18, and supporting atthe opposite end a gripping member 19 for gripping one reel 3 at a time.Platform 15 is set to a given position with respect to machine 1, andcomprises a lifting device 20, and locating elements 21 for locatingpallet 16 with respect to platform 15.

Gripping member 19 is bell-shaped with an axis A, and, as shown moreclearly in FIG. 2, comprises an annular plate 22 in which are formedsuction holes 23 selectively connectable to a vacuum source not shown,and a cavity 24 housing three distance sensors 25. Gripping member 19has a contact sensor 26 located along annular plate 22 and for arrestingmanipulator 14 when gripping member 19 contacts a reel 3.

With reference to FIG. 3, each sensor 25 comprises an emitter 27 foremitting a beam of electromagnetic waves; and a receiver 28 forreceiving a beam of electromagnetic waves. Emitter 27 is located at adistance D1 from receiver 28 and emits a beam so oriented that a surface(face 9 of reel 3) facing, parallel to and located a given distance D2from annular plate 22 reflects the beam in a position in which receiver28 is able to pick up the reflected beam. Distance D2 is measuredparallel to axis A and axis 5, and distance D1 is measured perpendicularto axis A. Receiver 28 is defined by a number of adjacent cells 29sensitive to electromagnetic waves, so that receiver 28 is able toreceive the reflected beam when the reflecting surface lies within agiven range I (parallel to axes 5 and A) about distance D2. Withreference to FIG. 2, gripping member 19 is equipped with three sensors25, the emitters 27 and receivers 28 of which are equally spaced aboutaxis A of cavity 24 of gripping member 19.

With reference to FIG. 1, each pin 4 a, 4 b comprises an expansionspindle 30 having a tapered free end 31, and three sectors 32 movablebetween a closed position contacting one another, and an open positionin which they are forced against spool 6 of a reel 3 to hold reel 3 in agiven position about axis 12. As sectors 32 are opened, axis 5 of reel 3is positioned to coincide with axis 12 of the unwinding pin. In otherwords, spindle 30 is self-centering.

Feed device 2 is controlled by a control unit 33, which processes thesignals from sensors 25 and 26 and controls the movements of manipulator14, lifting device 20 and pins 4 a and 4 b.

In actual use, and with reference to FIG. 1, a pallet 16 of reels 3 isplaced on platform 15. Pallets 16 and reels 3 are of standard size, sothat the arrangement of reels 3 on pallet 16 varies within relativelysmall limits. Consequently, reels 3 on pallet 16 on platform 15 arearranged with a certain tolerance about respective given positionsmemorized in control unit 33; and, to pick up a reel 3 for supply tomachine 1, manipulator 14 positions gripping member 19 over one of reels3 whose position and height in a vertical direction D are roughly known.Manipulator 14 positions gripping member 19 at or roughly at distance D2from the top lateral face 9 of reel 3, as shown in FIGS. 3 and 4.

Given the approximate positions of reels 3, gripping member 19 can beset to the FIG. 3 or 4 position, i.e. with axis A of gripping member 19close to or at hole 7 in reel 3. For the sake of simplicity and togeneralize the concept underlying the present invention, gripping member19 in FIGS. 3 and 4 is equipped with one distance sensor 25. Whengripping member 19 is positioned over reel 3, annular plate 22 ismaintained horizontal so as to be parallel to lateral face 9 of reel 3.With reference to the FIG. 3 case, emitter 27 emits a beam ofelectromagnetic waves, which is reflected by lateral face 9 at a givenpoint K1. Face 9 lying within range I of distance D2 enabling receiver28 to receive the reflected beam, the reflected beam strikes one ofcells 29 of receiver 28, which transmits a signal to control unit 33,which in turn determines the location of reflection point K1 on lateralface 9 of reel 3. When reflection point K1 is located on face 9,gripping member 19 and reel 3 are not sufficiently aligned to ensurereel 3 is positioned correctly on unwinding in 4 a, 4 b, so grippingmember 19 is moved about its initial position in directionsperpendicular to direction D. At each movement, sensor 25 determineswhether reflection point K1 lies on lateral face 9 or in hole 7. Whenthe beam enters hole 7, reflection point K1 may be located on a supportunderneath reel 3 or along an inner face of spool 6. Whichever the case,when the beam enters hole 7, the reflected beam does not strike receiver28, on account of the reflecting surface not being within range I ofdistance D2, so that the absence of a receiving signal by receiver 28combined with an emission signal by emitter 27 indicates gripping member19 is correctly aligned with reel 3, or at least is aligned sufficientlyto ensure correct transfer of reel 3 from gripping member 19 tounwinding pin 4 a, 4 b.

Manipulator 14 lowers gripping member 19 towards reel 3 in direction Duntil sensor 26 detects plate 22 contacting lateral face 9; suctionholes 23 are then connected to the vacuum source, and reel 3 is raisedfor transfer to pin 4 b; gripping member 19 and reel 3 are positionedover pin 4 b so that axis A of member 19 is aligned with axis 12 of pin4 b; gripping member 19 is lowered onto pin 4 b in direction D so thatpin 4 b engages hole 7, even if axis 5 of reel 3 is not perfectlyaligned with pin 4 b, by virtue of the tapered free end 31 of spindle30; reel 3 is released by gripping member 19; and spindle 30 is expandedso that axis 5 of reel 3 coincides with axis 12 of unwinding pin 4 b.

In other words, before a reel 3 is picked up, a check is made todetermine whether reference point K1 of gripping member 19 lies insidehole 7 of reel 3. Obviously, the more reference points there are, themore accurately and faster hole 7 of reel 3 is determined.

FIGS. 5, 6 and 7 show, schematically, the case in which gripping member19 comprises three distance sensors 25, as in FIG. 2. In FIG. 5, threeseparate reflection points K1, K2, K3 are located on lateral face 9 ofreel 3, which is tantamount to the FIG. 3 situation, so that a number ofmovements about the initial position are required to determine thelocation of hole 7. This may result in the situation shown in FIG. 6, inwhich two points K1 and K2 are located on lateral face 9, and point K3lies in hole 7 and is therefore not picked up by receiver 28. Controlunit 33, however, knows the hypothetical position of point K3 andcommands a movement in the direction of arrow F1, i.e. towards point K3,to also bring points K1 and K2 inside hole 7.

Alternatively, as shown in FIG. 7, one point K1 may be located onlateral face 9 of reel 3, and points K2 and K3 inside hole 7. In whichcase, manipulator 14 moves gripping member 19 in a directionperpendicular to the line joining hypothetical points K2 and K3 and inthe direction of arrow F2 until point K1 also lies inside hole 7.

In one variation, control unit 33 does not know the height of reels 3 indirection D, but only the approximate arrangement of reels 3 in theplane perpendicular to direction D, so that, when positioned over a reel3, gripping member 19 is lowered into contact with reel 3; and, uponsensor 26 indicating contact between gripping member 19 and reel 3,gripping member 19 is set to or within the range about distance D2 so asto effectively determine the position of gripping member 19 with respectto reel 3, as in the previous case.

The method and device according to the present invention areparticularly advantageous by only requiring the processing of arelatively small number of data items.

When the position of gripping member 19 with respect to reel 3 isdetermined using only one reference point K1, reel 3 is centered onunwinding pin 4 a or 4 b by expansion spindle 30. When the position ofgripping member 19 with respect to reel 3 is determined using threereference points K1, K2, K3, axis A of gripping member 19 can be alignedwith axis 5 of reel 3 by simply selecting three reference points K1, K2,K3 located, at distance D2 from a reflecting surface, along ahypothetical circumference slightly smaller in diameter than hole 7, sothat reel 3 is transferred to pin 4 a or 4 b with no need for centeringby a self-centering spindle 30. In a further variation not shown, thesame result as with three reference points can also be achieved withonly two separated, at distance D2 from a reflecting surface, by adistance slightly less than the diameter of the reel hole.

1. A method of feeding reels to a machine from a store of reels close tosaid machine; each reel having an axis , a central hole which isengagable by an unwinding pin on said machine, and two flat facesperpendicular to said axis ; and the method comprising the steps of:positioning said gripping member facing one of said flat faces of areel; bringing said gripping member into contact with said flat face;withdrawing said gripping member perpendicularly to said flat face toposition the gripping member at a second distance from the flat face orwithin a range (I) about said second distance; determining whether atleast one reference point of a gripping member of a manipulator liesinside the hole of a reel in the store; picking up said reel by thegripping member when the reference point lies inside the hole of saidreel; and transferring said reel from said gripping member to saidunwinding pin.
 2. The method as claimed in claim 1, further comprisingemitting a beam of electromagnetic waves onto a reel by an emitter onsaid gripping member; said reference point being the reflection point ofsaid emitted beam.
 3. The method as claimed in claim 2, wherein saidgripping member comprises a receiver located at a first distance fromsaid emitter so as to pick up the reflected beam when said flat face islocated at said second distance, parallel to said axis, from saidgripping member, and the reflection point lies on said flat face.
 4. Themethod as claimed in claim 3, wherein said receiver comprises a numberof adjacent cells sensitive to electromagnetic waves, so as to pick upthe reflected beam when the flat face lies within the given range (I),parallel to said axis, about said second distance from the grippingmember, and the reflection point lies on said flat face.
 5. The methodas claimed in claim 3, further comprising moving said gripping memberparallel to said flat face when said receiver picks up the reflectedbeam.
 6. The method as claimed in claim 5, further comprising picking upsaid reel when said receiver does not pick up the reflected beam.
 7. Themethod as claimed in claim 3, wherein said gripping member comprisesthree distance sensors; each distance sensor comprising one of saidemitters and one of said receivers; each distance sensor generating aresponsive reference point; and said gripping member picking up a reelwhen none of the receivers pick up the respective reflected beams. 8.The method as claimed in claim 1, further comprising determining saidcontact between the gripping member and the flat face by a sensor.
 9. Adevice for feeding reels to a machine from a store of reels close tosaid machine; each reel having an axis, a central hole which isengagable by an unwinding pin on said machine, the device comprising: amanipulator having a gripping member for picking up a reel from saidstore when at least one reference point of the gripping member liesinside the hole of said reel; a control unit, which commands a movementof the manipulator to move said gripping member for positioning saidgripping member facing one of said flat faces of a reel; bringing saidgripping member into contact with said flat face; and withdrawing saidgripping member perpendicularly to said flat face to position thegripping member at a second distance from the flat face or within arange (I) about said second distance.
 10. The device as claimed in claim9, further comprising an emitter located on said gripping member to emita beam of electromagnetic waves directed onto the reel; said referencepoint being a reflection point of the said emitted beam.
 11. The deviceas claimed in claim 10, further comprising a receiver for picking up areflected beam when the reflection point lies on said flat face, and notfor picking up the reflected beam when the reflection point lies insidethe hole.
 12. The device as claimed in claim 11, wherein the receiver islocated at a first distance from said emitter so as to pick up thereflected beam when said flat face is located at said second distance,parallel to said axis, from gripping member, and the reflection pointlies on said flat face.
 13. The device as claimed in claim 12,characterized in that wherein said receiver comprises a number ofadjacent cells sensitive to electromagnetic waves, so as to pick upreflected beam when the flat face lies within a the given range (I),parallel to said axis, about said second distance from the grippingmember, and the reflection point lies on said flat face.
 14. The deviceas claimed in claim 11, wherein the control unit commands a movement ofthe manipulator to move said gripping member parallel to said flat facewhen the reflection point lies on said flat face.
 15. The device asclaimed in claim 14, wherein said gripping member comprises an annularplate having suction holes to pick up said reel when said reflectionpoint lies inside the hole of said reel and the plate is positionedcontacting said flat face.
 16. The A-device as claimed in claim 12,wherein said gripping member comprises three distance sensors; eachdistance sensor comprising a said emitter and a said receiver; thedistance sensors generating distinct respective reference points; andsaid gripping member picking up a reel when the reference points all lieinside the hole of the reel.
 17. The device as claimed in claim 9,further comprising a platform for supporting said store of reels in agiven position with respect to said machine and to said manipulator. 18.The device as claimed in claim 10, wherein said store is a pallet ofreels.
 19. The device as claimed in claim 17, wherein said platformcomprises a lifting device.
 20. The device as claimed in claim 9,wherein said unwinding pin comprises a self-centering spindle.
 21. Thedevice as claimed in claim 20, wherein said self-centering spindlecomprises a tapered free end.